Scientists solve 1840s space weather mystery

Researchers reexamined a long-cited 1871 Nature report that claimed a “very intense magnetic disturbance” delayed an Exeter express on October 18, 1841, and concluded the year is a typographical error. Wild and co-authors cross-checked railway timetables, construction records, contemporary newspapers, Greenwich magnetograms and sunspot observations, and the publisher’s original issue (hand-annotated “N. J. Holmes”). The South Devon line between Exeter and Plymouth did not open until 1846, timetables show a 10:05 pm express only from 1848-49, and strong geomagnetic activity is documented on October 18-19, 1848. Taken together, the archival evidence points to 1848, not 1841, as the date of the reported disturbance and likely attributes the anonymous Nature note to Nathaniel John Holmes.

Correcting the date shifts the timeline of early technology-impairing space weather: the earliest confirmed disruption remains a March 1847 incident that produced spontaneous currents in Midland Railway telegraphs during a brilliant aurora. The work underscores that geomagnetic storms affected nascent electrical infrastructure well before the famous 1859 Carrington Event, and it demonstrates how archival magnetograms, astronomical observations and historical records can refine understanding of past space-weather events that inform modern risk assessment for electricity grids and communications systems.